list-unreleased: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/list-unreleased - from package: devscripts

You may install the required package with command apt-get install {package}

Error in other languages:
list-unreleased: bevel nie gevind nie
list-unreleased: comandă negăsită
list-unreleased: comando não encontrado
list-unreleased: commande introuvable
list-unreleased: command not found
list-unreleased: käsku ei ole
list-unreleased: không tìm thấy lệnh
list-unreleased: komanda nerasta
list-unreleased: Kommando nicht gefunden.
list-unreleased: kommandot finns inte
list-unreleased: komut yok
list-unreleased: nie znaleziono polecenia
list-unreleased: níor aimsíodh an t-ordú
list-unreleased: no se encontró la orden
list-unreleased: no s'ha trobat l'ordre
list-unreleased: opdracht niet gevonden
list-unreleased: parancs nem található
list-unreleased: perintah tidak ditemukan
list-unreleased: príkaz nenájdený
list-unreleased: příkaz nenalezen
list-unreleased: команда не найдена
list-unreleased: командата не е открита
list-unreleased: 命令找不到
list-unreleased: コマンドが見つかりません